UVa/108 - Maximum sum/p108.cpp

   1 #include <iostream>
   2 #include <stdio.h>
   3
   4 using namespace std;
   5
   6 int m[203][203], dp[203][203];
   7
   8 int main(){
   9   int n;
  10   cin >> n;
  11   memset(m, 0, sizeof(m));
  12   memset(dp, 0, sizeof(dp));
  13   for (int i=1; i<=n; ++i)
  14     for (int j=1; j<=n; ++j)
  15       cin >> m[i][j];
  16
  17   dp[1][1] = m[1][1];
  18   for (int i=1; i<=n; ++i)
  19     for (int j=1; j<=n; ++j)
  20       dp[i][j] = dp[i][j-1] + m[i][j] + dp[i-1][j] - dp[i-1][j-1];
  21
  22
  23 //   cerr << "m es:\n";
  24 //   for (int i=0; i<=n+1; ++i){
  25 //       for (int j=0; j<=n+1; ++j)
  26 //      cerr << m[i][j] << " ";
  27 //       cerr << endl;
  28 //   }
  29 //   cerr << "\ndp es:\n";
  30 //   for (int i=0; i<=n+1; ++i){
  31 //       for (int j=0; j<=n+1; ++j)
  32 //      cerr << dp[i][j] << " ";
  33 //       cerr << endl;
  34 //   }
  35
  36   int max = m[0][0];
  37   for (int i=n; i>=1; --i)
  38     for (int j=n; j>=1; --j)
  39       for (int k=1; k<=i; ++k)
  40         for (int l=1; l<=j; ++l){
  41           int a = dp[i][j] - dp[i-k][j] - dp[i][j-l] + dp[i-k][j-l];
  42           if (a > max)
  43             max = a;
  44         }
  45   cout << max << endl;
  46
  47
  48 }